2006 Prius Rough Idle after start

This could be normal if your engine has not warmed up properly. Ever compare it to other Gen2 cars? Sometimes you just can't improve on what's normal behavior

 

normal.

 

I got same situation. Some times, I felt the entire body tremble when the engine turning off in front of the red traffic light.

 

Sounds like normal behavior, if it is the first time after startup.

 

Sounds completely normal. I have found tightening or replacing motor mounts alleviates a lot of the jump, but it is not a necessity to do.

 

How involved is that process?

 

Mine does this too. In fact my dealer told me that it is nothing to worry about as long as there are no trouble codes being thrown.

 

Motor mounts would have nothing to do with the motor running rough. If you haven't kept up with the maintenance, I would suggest getting everything up to date before further diagnosis.

 

My 2007 has done this since I bought it and EVERY maintenance has been done on time or before (I am OCD), lol. Sometimes its very noticeable, sometimes not at all. I now have 95,000 miles.

As a matter of fact, this morning it was idling really rough after I started it - I just figured it was trying to tell me that it was grumpy because it needed a car wash real bad

 

Mine does it too, it seems like it runs rough for a few seconds at cold start-up, but goes away quickly. I haven't found the cause, I just accept it. I know that's not helpful... but a good idea for general maintenance would be to remove the Mass Air Flow sensor and clean the MAF every now and then, with the MAF out, you can also safely clean the throttle body. Both are good items to clean to make the Prius run smooth.

Here's a link to a post: Cleaning MAF Sensor | PriusChat

Toyota Prius: How to Clean the Throttle Body - PriusDIY.com
In this set of instructions they don't remove the air box to get to the throttle body. I recommend removing the entire air box just so you can get closer and see how dirty / clean everything really is...

 

The reason is that, in stage 1, the VVTi timing is set so the ICE runs very lean. In this configuration the engine runs rough (relatively speaking) and does not develop as much power (again, relatively speaking), but also runs hotter, so heats up quicker. This stage lasts about 50 secs (seems a lot longer) and at about 40 secs you can hear and feel the valve timing change (particularly if you're stationary at the time) to a more normal setting before it cuts out. During this warm up stage and to compensate for the lower power from the ICE, propulsion is exclusively EV, even though the ICE is running--unless you ask for power, then "your wish is my command". If you can, you should allow S1 to complete to get best fuel economy. To do this though, will require a bit more of a conservative approach at startup/setting off.

You can read more about the 5 stages of warm up by clicking on the link (Hybrid Warm up) in my signature.

 

If you are really interested in a fuel additive then use Chevron Techron Progard Fuel Injector cleaner, based on my research and experience using all kinds of additives this one works the best for prius, use the 20 oz bottle in a 3/4 filled tank or more. However I have the same issue but seems like I might have a little more to it as well, changing the plugs did not help me as well, while cold if I depress the gas pedal all the way I can hear misfires, I checked the throttle body when cold and tried to open it but failed as it was too hard, once I turned on the car and it got warmed then it was easy to open / close by hand. I have ordered a used one and will replace it tomorrow to see if that helps.

 

You should be able to open the butterfly by hand when cold or warm. The spring is probably bone dry. Spray some lube on it.

Also in LA you dsont need the 2 coolant hoses hooked to the TB. Just by a pex barrel and bypass the TB with the coolant. Did that on my 07 the right after I bought it new.
seco

 

OK so replaced the throttle body assembly yesterday and it fixed my problem. If interested see this thread.
2008 Prius losing power - Need troubleshooting help. | PriusChat

 

Removing the 190 coolant to the TB helps increase its life. Not needed in southerly climes.

 

Mine has done this since from day 1 when I bought it brand new.

 

Hmmm.,...my 07 bought new runs real good at start up. Goes through its various vvt modes till warm up but other than that I can drive away instantly no issues...

 

LOL! I'm guessing this isn't a problem. BUT...I hate that answer from service departments.

It's getting so real mechanics are rare, and service techs won't investigate or evaluate "anything" without the computer leading the way by throwing a code.

With all due respect to today's automobiles computer systems, which are amazing and also very sophisticated, pardon me if I think my automobile might be able to develop a problem that just might not be revealed immediately with the appearance of a code.

Years back I got rear ended with my Honda Fit. It was driveable, the outward damage was minimal...common rear bumper. I just wanted the service department to "check it out" ....any leaks, any visible damage to the frame...

The service adviser looks at me and gives me the old "If there are no codes, it's fine".

I practically had to beg them to put it up on the rack and just inspect it. In fact, I'm not really sure they ever did, when I insisted, they drove it back into the unviewable service area and kept it for about 1/2 hour, then TOLD me it looked fine.

I think the sophistication of todays machines which can and will self diagnosis a whole lot of problems and conditions, and give warning are great. But I don't like how it's becoming more and more, that a service department won't even deal with a problem "unless" there is a code.

 

HaHa! I thought his reply was a bit lame too, but I just didn't admit it here in the forum.